DESCRIPTION: Obsessive compulsive disorder (OCD) is a severe, prevalent and chronically disabling disorder that often emerges during childhood. Nonetheless, pediatric OCD remains an understudied disorder. One reason is that there are too few researchers with sufficient skills and understanding in both developmental neurobiology and neuropsychopharmacology. Treatment studies using biological markers as moderator (present at baseline) and mediator (changing with treatment) may potentially lead to a mechanistic understanding of the pathogenesis and maintenance of the illness, which may in turn result in the development of new diagnostic and treatment approaches. This is critical because at least one third of patients do not respond at all, even after apparently adequate treatment trials. Treatment-refractory patients are also more likely to have early onset of illness. Preliminary studies suggest a reversible glutamatergically mediated thalamocortical-striatal dysfunction in OCD that may serve as a pathophysiological and treatment response marker. In this context, the candidate's chief aim is to use time liberated by the K24 Award to develop, evaluate and disseminate biological outcome markers of OCD and determine their relevance for improved diagnostic assessment and treatment. To this end, the K24 career development plan (1 )furthers the candidate's knowledge in clinical neuroscience emphasizing the integration and translation of brain imaging measurement as it relates to neurodiagnostic assessment and treatment, 2) furthers the candidates knowledge in the conduct and design of relevant clinical trials for treatment development, and (3) emphasizes knowledge dissemination of the translational components of this research, including a proposed T32 training grant focused on psychopathology and treatment of pediatric mental disorders. The K24 research plan centers on ongoing and proposed treatment outcome studies using brain imaging to help elucidate neurobiological markers in childhood OCD. The K24 will advance sustained practical and theoretical contributions to the candidates chosen research area.